A device for determining the position of a semiconductor substrate on a rotation device having a rotational axis, including a direction of rotation detecting unit for determining the rotational state of the rotation device, and also including at least one light source and at least one receiver which is photo-sensitive to the light from the light source, wherein at least one light beam emitted by the light source is directed toward the edge of the semiconductor substrate and passes said edge to at least a partial extent. The light of the light beam which has passed to at least a partial extent is then detected at least partially by the receiver.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A device for determining the position of a semiconductor substrate on a rotation device having a rotational axis, said semiconductor substrate having a peripheral edge, said device comprising: a detecting unit for determining the rotational state of the rotation device; at least one light source, said at least one light source comprising a modulating device that produces a light beam having a specific variation over time; at least one receiver which is photo-sensitive to the light from the light source, said at least one receiver comprising a demodulating device configured to demodulate said light beam detected by said at least one receiver; wherein during rotation of said semiconductor substrate on said rotation device, said at least one light source emits a light beam toward said peripheral edge of said semiconductor substrate such that said light beam partially intersects and partially passes over said peripheral edge, and wherein said at least one receiver detects said light beam which has partially passed over said peripheral edge and determines whether there is any temporary variation over time in the intensity of said detected light beam.
2. The device of claim 1 , wherein said at least one light source and said at least one receiver are arranged outside said process chamber, said light beam emitted from said at least one light source passing through at least one opening that is optically transparent to said light beam.
3. The device of claim 1 , wherein said device further comprises a ring shaped object surrounding said semiconductor substrate.
4. The device of claim 3 , wherein said ring shaped object is spaced from said semiconductor substrate.
5. The device of claim 1 , wherein said at least one receiver produces a receiver signal responsive to said intensity of said light beam detected by said receiver.
6. The device of claim 5 , wherein said device further comprises a processing unit that receives said receiver signal and produces an output signal comprising a measure for the position of the semiconductor substrate.
7. The device of claim 6 , wherein said device further comprises a control unit, said control unit providing for the correction of said position of said semiconductor substrate based on said output signal of said processing unit.
8. The device of claim 1 , wherein said device comprises at least two receivers arranged at an angle relative to said rotational axis.
9. The device of claim 1 , wherein said device comprises at least one beam splitter configured to split the light beam emitted by the light source into at least two separate light beams.
10. The device of claim 1 , wherein said device comprises at least two receivers arranged at an angle relative to said rotational axis and at least two light sources arranged at an angle relative to said rotational axis.
11. The device of claim 1 , wherein said detecting unit comprises a transmitter and a receiving unit, said transmitter and receiving unit being spaced from said rotation device to avoid interference from said semiconductor substrate positioned on said rotation device.
12. The device of claim 1 , wherein said detecting unit produces at least one signal when said semiconductor substrate is loaded or unloaded into said device.
13. The device of claim 1 , wherein said at least one receiver comprises spatially resolving elements.
14. The device of claim 1 , wherein said light beam has a defined beam profile.
15. The device of claim 14 , wherein said light beam profile is between 2 mm and 6 mm at said peripheral edge of said semiconductor substrate.
16. A method for determining the position of a semiconductor substrate on a rotation device having a rotational axis, said semiconductor substrate having a peripheral edge, said method comprising: rotating said semiconductor substrate with said rotation device; determining the rotational state of the rotation device; generating with at least one light source comprising a modulating device a light beam having a specific variation over time; during rotation of said semiconductor substrate, emitting the light beam toward said peripheral edge of said semiconductor substrate such that said light beam partially intersects and partially passes over said peripheral edge; detecting with at least one receiver said light beam which has partially passed over said peripheral edge; demodulating with a demodulating device the light beam detected by the at least one receiver; and determining whether there is any temporary variation over time in the intensity of said detected light beam.
17. The method of claim 16 , wherein said semiconductor substrate is rotated through at least one revolution by the rotation device during the step of detecting said light beam,
18. The method of claim 16 , wherein said method further comprises determining the position of said semiconductor substrate based at least in part on said detection of said light beam by said at least one receiver.
19. The method of claim 16 , wherein said method comprises correcting said position of said semiconductor wafer based at least in part on said determined position of said semiconductor wafer.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 26, 2004
June 29, 2010
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